/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.reactive.function.server;

import java.util.Collection;
import java.util.Map;
import java.util.function.Consumer;

import reactor.core.publisher.Mono;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseCookie;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.MultiValueMap;

/**
 * Rendering-specific subtype of {@link ServerResponse} that exposes model and template data.
 *
 * @author Arjen Poutsma
 * @author Juergen Hoeller
 * @since 5.0
 */
public interface RenderingResponse extends ServerResponse {

    /**
     * Return the name of the template to be rendered.
     */
    String name();

    /**
     * Return the unmodifiable model map.
     */
    Map<String, Object> model();


    // Builder

    /**
     * Create a builder with the template name, status code, headers and model of the given response.
     *
     * @param other the response to copy the values from
     * @return the created builder
     */
    static Builder from(RenderingResponse other) {
        Assert.notNull(other, "Other RenderingResponse must not be null");
        return new DefaultRenderingResponseBuilder(other);
    }

    /**
     * Create a builder with the given template name.
     *
     * @param name the name of the template to render
     * @return the created builder
     */
    static Builder create(String name) {
        Assert.notNull(name, "'name' must not be null");
        return new DefaultRenderingResponseBuilder(name);
    }


    /**
     * Defines a builder for {@code RenderingResponse}.
     */
    interface Builder {

        /**
         * Add the supplied attribute to the model using a
         * {@linkplain org.springframework.core.Conventions#getVariableName generated name}.
         * <p><emphasis>Note: Empty {@link Collection Collections} are not added to
         * the model when using this method because we cannot correctly determine
         * the true convention name. View code should check for {@code null} rather
         * than for empty collections.</emphasis>
         *
         * @param attribute the model attribute value (never {@code null})
         */
        Builder modelAttribute(Object attribute);

        /**
         * Add the supplied attribute value under the supplied name.
         *
         * @param name  the name of the model attribute (never {@code null})
         * @param value the model attribute value (can be {@code null})
         */
        Builder modelAttribute(String name, @Nullable Object value);

        /**
         * Copy all attributes in the supplied array into the model,
         * using attribute name generation for each element.
         *
         * @see #modelAttribute(Object)
         */
        Builder modelAttributes(Object... attributes);

        /**
         * Copy all attributes in the supplied {@code Collection} into the model,
         * using attribute name generation for each element.
         *
         * @see #modelAttribute(Object)
         */
        Builder modelAttributes(Collection<?> attributes);

        /**
         * Copy all attributes in the supplied {@code Map} into the model.
         *
         * @see #modelAttribute(String, Object)
         */
        Builder modelAttributes(Map<String, ?> attributes);

        /**
         * Add the given header value(s) under the given name.
         *
         * @param headerName   the header name
         * @param headerValues the header value(s)
         * @return this builder
         * @see HttpHeaders#add(String, String)
         */
        Builder header(String headerName, String... headerValues);

        /**
         * Copy the given headers into the entity's headers map.
         *
         * @param headers the existing HttpHeaders to copy from
         * @return this builder
         * @see HttpHeaders#add(String, String)
         */
        Builder headers(HttpHeaders headers);

        /**
         * Set the HTTP status.
         *
         * @param status the response status
         * @return this builder
         */
        Builder status(HttpStatus status);

        /**
         * Set the HTTP status.
         *
         * @param status the response status
         * @return this builder
         * @since 5.0.3
         */
        Builder status(int status);

        /**
         * Add the given cookie to the response.
         *
         * @param cookie the cookie to add
         * @return this builder
         */
        Builder cookie(ResponseCookie cookie);

        /**
         * Manipulate this response's cookies with the given consumer. The
         * cookies provided to the consumer are "live", so that the consumer can be used to
         * {@linkplain MultiValueMap#set(Object, Object) overwrite} existing cookies,
         * {@linkplain MultiValueMap#remove(Object) remove} cookies, or use any of the other
         * {@link MultiValueMap} methods.
         *
         * @param cookiesConsumer a function that consumes the cookies
         * @return this builder
         */
        Builder cookies(Consumer<MultiValueMap<String, ResponseCookie>> cookiesConsumer);

        /**
         * Build the response.
         *
         * @return the built response
         */
        Mono<RenderingResponse> build();
    }

}
